This invention relates to an apparatus for making or breaking a connection between first and second tubular members and for measuring and displaying the torque supplied by the apparatus to such tubular members to make or break the connection.
Apparatus for supplying torsion forces to tubular members in order to make or break a connection between such tubular members are well known to those skilled in the art. In the oil and gas industry, these apparatus are generally known as "power tongs." In the use of power tongs to make and break connections between tubular members, it is often desirable to measure the torque imparted to the tubular members in order to assure proper assembly of the connection and to aid inspection during disassembly to the connection. Numerous methods and apparatus have been developed for aiding in determining the torque applied to a connection by power tongs. Certain of these methods and apparatus are disclosed in the following U.S. Pat. Nos.: 2,535,667; 3,368,396; 3,589,179; 3,606,664; and 3,745,820.
It is an object of this invention to provide an improved power tong apparatus which will accurately measure the amount of torque applied to a connection between tubular members in a manner independent of the physical constraints and mounting of the power tong apparatus.
In the improved power tong apparatus according to this invention, there is provided an apparatus for supplying torsion forces to a first tubular member in order to make or break a connection between the first tubular member and a second tubular member and for measuring and displaying the torque supplied to such tubular members. The power tong apparatus includes power means for supplying rotative forces and a rotatable transfer shaft integrally connected with the power means for generating high torque forces. The power tong apparatus includes a lateral drive means which couples the transfer shaft to the first tubular member whereby the high torque forces are transmitted from the transfer shaft to the first tubular member. The power tong apparatus includes means associated with the transfer shaft for transducing the angular deformation of the transfer shaft, due to torsion, into an electrical signal representative thereof. The transducer means are associated with the transfer shaft intermediate the location at which the transfer shaft connects with the power means and the location at which the transfer shaft is coupled to the lateral drive means. A slip ring assembly is secured to a selected end of the transfer shaft for conducting electrical signals from the shaft as it rotates. Display means are electrically connected to the slip ring assembly for receiving the electrical signals generated by the transducer means and responsive thereto displaying the magnitude of the torque supplied to the first tubular member. The improved power tong apparatus according to this invention allows the operator of the power tong apparatus to measure accurately the amount of torque supplied to the connection and, since the torque is determined at a portion of the transfer shaft which is internal to the power tong apparatus, the presence or absence of a backup tool to hold the second tubular member from rotating, the mounting of the power tong apparatus on its side for pipe yard work, or the mounting of the tong at an angle, as in slant hole work, makes no difference in the measurement of the torque. Thus, the improved power tong apparatus according to this invention accurately measures the amount of torque supplied to the connection between tubular members in a manner independent of the physical constraints and mounting of the power tong apparatus.